Spirit hectograph process



Patented Dec. 9, 1941 srnur HECTOGRAPH PROCESS Douglas A. Newman, Little Neck, Long Island, a N. Y., assignor to Columbia Ribbon and Carbon Manufacturing Company, Inc., Glen Cove, N. Y.

No Drawing. Substituted for abandoned applica tion Serial No. 328,878, April 10, 1940. This application February 21, 1941, Serial No. 380,001

7 Claims.

My invention relates to the art of hectographic copying by the spirit process and more particularly to an improvement in respect to the number and clarity of the duplicate copies which can be drawn from the master copy. This application is a substitute for application Serial No. 328,878, filed April 10. 1940.

The object of my invention is to provide a method whereby substantially the entire deposit of hectographic ink which has been placed upon the surface of the master copy may be transferred from the master copy to the duplicate copies made therefrom.

Another object of my invention is to provide a method whereby a more constant and unvarying color of the copies may be maintained throughout the successive copies made by the spirit process.

In the spirit hectograph process a master copy of the subject matter is made by printing, typing, drawing or otherwise, with hectograph ink, in reverse, upon a sheet of paper. Successive sheets of paper, each previously moistened with a suitable liquid or spirit which is a solvent of the hectograph ink, and herein called the spirit liquid, are then brought into pressure contact with the surface of the master copy with the result that a small fraction of the hectograph ink is dissolved from the master copy by the spirit liquid with which the paper is moistened and is so transferred from the master copy to the duplicate copy sheet, thus producing a duplicate copy upon the paper so treated.

A hectograph ink is usually purple in color and consists of a dye material, or a combination or mixture of dye materials, mixed or intimately incorporated with, and suspended in, a wax or wax-like substance called a matrix. These dyes are soluble in the spirit liquid with which the duplicate copy sheets are moistened. As successive copy sheets, previously moistened with the spirit liquid, are brought into pressure contact with the master copy, some of the dye in the ink is dissolved by the spirit liquid and so transferred from the master copy to the duplicate copy.

The wax matrix of the ink in which the dyes are mixed and suspended is less soluble in the spirit liquid with which the duplicate copy sheet is moistened than are the dyes. The result is that the dye is gradually dissolved out of the outermost layer of wax by the spirit liquid of successive duplicate copy sheets, leaving a wax surface containing a gradually lessening quanweaker and weaker even though there is still an adequate supply of ink containing dye beneath the coating of wax which is unusable because of the presence and interference of the overlying protective layer of exhausted wax on thesurface.

When a black hectograph ink is desired, it is often a combination of several dyes of different colors so proportioned and combined that they produce a dark ink which is nearly black. These dyes are mixed with, and suspended in, a wax or waxy substance. Not all of the several dyes which are used to simulate black are of equal solubility in the fluid used to moisten the copy sheets.

The result of this difference in solubility of the dyes in the spirit liquid is a gradual change in color of the duplicate copies made from the master copy. The first copies taken off have a color in which the dye which is most soluble in the spirit liquid tends to predominate.

As this more soluble dye is gradually dissolved out of the surface layer of the hectograph ink on the master copy, its color becomes less dominant in the copies and later as the less soluble dyes are dissolved their color tends to-predomihate. The result is a gradual change of color of the duplicate copies as the overlying layer of wax interferes with the free solution of underlying ink.

By the use of my invention, this change in color in the case of a so-called black ink is substantially eliminated by reason of the chemical actions herein described.

My invention is aimed at providing a method whereby this exhausted surface layer of wax is gradually and continuously removed during the normal operation of the duplicating process until substantially all of the ink on the master copy has been transferred to the duplicate copy sheets. I accomplish these objects in the following manner:

I incorporate in the hectograph ink used in making the master copy an added substance which, with another substance which I add to the spirit liquid with which the copy sheets are moistened, will react to produce a gas,

7 Thus I may incorporate in the ink an alkali carbonate or the like, and in the spirit an acid substance such that when the spirit liquid upon the moistened copy sheet is brought into pressure contact withfthe'ink on themaster copy a chemical reaction will take place between the acidand the carbonate resulting in the formation and liberation of a gas within the body of the ink on the surface of the master sheet? This evolution of gas tends to loosen and detach the surface portion of the wax matrix from which the dye has been dissolved by the spirit liquid and removed by the duplicate copy sheets.

Thus the layer of depleted wax is removed as fast as it becomes exhausted and a new surface of underlying ink s exposed. This action con tinues until the ink upon the master copy has been substantially exhaustedand transferred to the duplicate copies. By this method a substantially greater number of copies can be made from by weight and a suitable acid, such, for example,

as acetic acid, may be mixedvwith the spirit in the proportion of 1 to 2% by weight. While this combination of a carbonateof an alkali metal 'andan acid .is a preferred method of carrying out the invention, I find that many other combinations serve my purpose satisfactorily. I therefore do not wish to restrict my invention to ,any particular combination of substances. I find that almost any two substances, which when brought together in solution or in suspension or one in solution and the other in suspension will react to produce gas, may be used, provided that they have no harmful effect upon the ink or upon the equipment employed.

I therefore wish it to. be understood that I do not limit myself to any specific combination of substances for generating a gas within the body of the layer of hectograph ink upon the surface of the master copy. I have given an example of suitable substances so that one skilled in the art may practice my invention, the spirit of which is defined and set forth in the appended claims.

I claim: 1. The step in the methodof duplicating by the spirit hectograph process which comprises incor porating a substance in the hectograph ink and dissolving a second substance in the spirit liquid to be used therewith, said substances being capable of chemically reacting with each other at ordinary temperatures to produce a ga 2. The method of removing the outer layer of. waxy substance from the surface of hectograph ink on a master copy during the operation of taking duplicate. copies therefrom by the spirit proo; ess, which includes incorporating in the hectograph ink and in the spirit liquid, substances which are capable of co-reacting at ordinary temperatures to form a gas.

3. The method of removing the waxy substance from the surface of hectograph ink on a master copy during the operation of taking cop- I ies therefrom by the spirit method which includes the steps of incorporating a substance in the hectograph ink and incorporating another substance in the spirit liquid, said substances being capable 5. The method of hectographic copying by the spirit process which includes the use of a hectographic ink containing a carbonate and of a spirit liquid containing an acid capable of reacting with said carbonate to produce a gas.

6. The method of hectographic copying by the spirit process which includes the use of a hectographic ink containing sodium carbonate and of a spirit liquid containing acetic acid.

'7. The method of hectographic copying by the spirit process which includes the use of a hectorgraph ink containing about five per cent of sodi= um carbonateand of a spirit liquid containing about two percent of acetic acid.

DOUGLAS A. NEWMAN. 

